diff --git a/utils/nightly/gmsh.ctest b/utils/nightly/gmsh.ctest
index b11848661508e33817b762ee49674da3d85a2323..a7e1d0ce91c4cc85eda853975073d764cbb271e5 100644
--- a/utils/nightly/gmsh.ctest
+++ b/utils/nightly/gmsh.ctest
@@ -35,8 +35,8 @@ if(CTEST_BUILD_OPTIONS_QUOTED)
   set(CTEST_CONFIGURE_COMMAND "${CTEST_CONFIGURE_COMMAND} \"${CTEST_BUILD_OPTIONS_QUOTED}\"")
 endif(CTEST_BUILD_OPTIONS_QUOTED)
 if(WITH_COVERAGE AND CTEST_COVERAGE_COMMAND)
-  set(CTEST_CONFIGURE_COMMAND "${CTEST_CONFIGURE_COMMAND} -DCMAKE_CXX_FLAGS:STRING=-g -O0 -fprofile-arcs -ftest-coverage")
-  set(CTEST_CONFIGURE_COMMAND "${CTEST_CONFIGURE_COMMAND} -DCMAKE_C_FLAGS:STRING=-g -O0 -fprofile-arcs -ftest-coverage")
+  set(CTEST_CONFIGURE_COMMAND "${CTEST_CONFIGURE_COMMAND} \"-DCMAKE_CXX_FLAGS:STRING=-g -O0 -fprofile-arcs -ftest-coverage\"")
+  set(CTEST_CONFIGURE_COMMAND "${CTEST_CONFIGURE_COMMAND} \"-DCMAKE_C_FLAGS:STRING=-g -O0 -fprofile-arcs -ftest-coverage\"")
 endif(WITH_COVERAGE AND CTEST_COVERAGE_COMMAND)
 set(CTEST_CONFIGURE_COMMAND "${CTEST_CONFIGURE_COMMAND} \"${CTEST_SOURCE_DIRECTORY}\"")
 
diff --git a/utils/nightly/gmsh_linux64_coverage.ctest b/utils/nightly/gmsh_linux64_coverage.ctest
index 1c7d1fb7b835a81c70b9f36eedd4ed8d6655cb4f..f269f9b295a365675932aa0489c0e5249f8b0083 100644
--- a/utils/nightly/gmsh_linux64_coverage.ctest
+++ b/utils/nightly/gmsh_linux64_coverage.ctest
@@ -16,6 +16,7 @@ set(WITH_MEMCHECK FALSE) # check memory with valgrind?
 #################################################################################
 set(CTEST_BUILD_NAME "Linux64-Coverage")
 set(OPT "-DGMSH_EXTRA_VERSION=${EXTRA_VERSION}")
+set(OPT "${OPT} -DENABLE_FLTK=0")
 set(OPT "${OPT} -DCMAKE_PREFIX_PATH:path=/usr/local/opencascade;/usr/local")
 set(OPT "${OPT} -DENABLE_NATIVE_FILE_CHOOSER:bool=FALSE")
 set(OPT "${OPT} -DPETSC_ARCH=linux_complex_mumps_seq")